Display screen having a graphical user interface for product substitution



The FIGURE is a front view of a display screen having a graphical user interface for product substitution showing our new design.

An example electronic device is shown in broken lines to illustrate environment. The remaining broken lines illustrate portions of the display screen having a graphical user interface for product substitution. The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a display screen having a graphical user interface for product substitution, as shown and described. 